Item Type: Electromagnetic Induction Coil
Material: PVC+Brass
Purpose: Middle and high school physics experiment
Applicable Experiments: Study electromagnetic induction, verify Lenz's law, study magnetic induction phenomenon
The outer diameter of the hole at the bottom of the original coil is: Approx. 22±1mm / 0.9±0.04in
The inner diameter of the hole at the bottom of the original coil is: Approx. 13±0.5mm / 0.5±0.02in
The height of the round hole at the bottom of the original coil: Approx. 60mm / 2.4in
The diameter of the hole at the bottom of the secondary coil is: Approx. 35±1mm / 1.4±0.04in
The inner diameter of the circular hole at the bottom of the secondary coil is: Approx. 49±1mm / 1.9±0.04in
The height of the round hole at the bottom of the secondary coil: Approx. 80mm / 3.1in
Soft Core Length: Approx. 85mm / 3.3in

How to use:

1. Study the phenomenon of electromagnetic induction: connect the two ends of the secondary coil B to the two terminals of the ammeter with wires;
When using one end of the bar magnet to quickly insert (or withdraw) the secondary coil, the pointers of the galvanometer are all deflected, indicating that there is an induced current in the secondary coil at this time. This phenomenon is called electromagnetic induction. On the contrary, if the magnet is fixed, the movement of the auxiliary coil will also produce the same phenomenon
2. Verify Lenz's Law
(1) Experimental method: Observe the change in the direction of current indicated in the galvanometer when the magnet is inserted or withdrawn, and when the polarity of the magnet changes;
(2) Connect the original coil to a 3-4V DC power supply, and put a single?pole switch and a 109 sliding rheostat in series in the circuit. The same phenomenon occurs when the original coil is used instead of the magnet to do the above experiment. Changing the direction of current flowing into the primary coil will change the direction of induced current in the secondary coil.
(3) According to the device in picture(2), first insert the primary coil into the secondary coil, and then energize the primary coil. When the switch is just turned on or just cut off, the magnetic flux passing through the secondary line diagram changes, which also occurs at this time. The current is induced, and the direction of the current is opposite. Change the direction of the current flowing into the primary coil and redo this experiment, the direction of the induced current in the secondary coil will also change.
(4) According to the device in picture (2), insert the primary coil into the secondary coil and connect the circuit, and then use the sliding rheostat to quickly change the current intensity through the primary coil (increase or decrease), and the secondary coil will also be Generate an induced current, and the direction of the induced current is the same as picture (3).
Synthesize the above experimental results and analyze it to verify Lenz's law.
3. Study the phenomenon of magnetic induction
Put the primary coil in the above picture 2 device into the secondary coil and wait for it to stand still. There is no induced current in the secondary coil. At this time, insert or withdraw the soft iron core C into or out of the central hole of the primary coil, the soft iron core is magnetized, and the magnetic field Increase or decrease. The change in the magnetic flux in the secondary coil also generates induced current. This experiment can explain both the magnetic induction and electromagnetic induction phenomena. During the experiments in the device picture (2), insert the soft iron core into the center hole of the original line diagram for demonstration, and the induced current in the secondary coil will increase the effect more obviously.